Welcome to the board! You'll find lots of great tips from some very knowledgeable cheesemakers.

Preparing a "mother culture" is fairly straight forward. First, buy a 1 litre box of trim milk (the UHT long life milk, that you can take out camping, etc). This milk has been pasturised to a very high temperature, which kills most of the bacteria (which is why it lasts so long). Anyway, open that and put 1/16th of a tea spoon of your culture in the milk. Put the top back, but not tightly (needs to breath and release gas, etc). Put the box in a warm spot, like the hot water cupboard. Leave it for 24 hours. Clean 3 ice cube trays, and soak in boiling water for a minute. Remove them, and let them cool a bit, then pour in the milk (it will be gluggy, like yogurt) and you will probably get a bit over 2.5 trays of cubes. Freeze them, and the next day remove the cubes from the trays and store them in a zip lock freezer bag. Label the bag with the name of the starter you used, and the date.

When you make cheese, use 2 or 3 cubes. One small pack of culture will let you make a lot of batches of mother culture.

Not sure if you can do this with prop. Shermi, which is used to give swiss cheese it's characteristic flavour and eyes.

To use the culture directly, one usually sprinkles around 1/8 - 1/4 tsp of culture on the milk, let it sit for 5 minutes, then stir it in. A lot of kits have packages of culture sized for one cheese, so you use the whole thing. As I say, if you make this into mother culture, you'll get near fifty cheeses or more from one single cheese package.

You can let cultured buttermilk sit out on the counter for a day to get it to go thick and gluggy and make ice cubes out of that. You can use that to make cheddars, gouda, and other "meso" cheeses (lower temperature cheeses, where the make never gets above 39 C). For makes that go over 39, use active culture yogurt (thermophillic) as your starter (1 or 2 tablespoons for a 10 litre cheese). These will let you make cheeses with decent results, and once you're confident, and have decided on what cheeses you want to make most, then you can invest in the specific cheese cultures for those cheeses (and make mother cultures, etc)

- Jeff

Logged

The wise do not always start out on the right path, but they do know when to change course.

I've used some well over a year old with success and don't notice any drop in effectiveness. I just made a new batch of my strep. therm. as the bag in the freezer was from 2010! I should have tested them to see how they were, but there weren't many left and they were pretty iced up. I've been making all meso cheeses for ages now.

- Jeff

Logged

The wise do not always start out on the right path, but they do know when to change course.

Jeff: I've always avoided UHP milk like the plague but you're saying you can use it and skip the heating to 200F / 95C or so before adding the starter to make a mother culture? To me this and the estimation of the useful life of the "cubes" is a huge revelation. I followed Sailor's instructions on mother cultures with good success (in my case using sterilized jars) but to be able to take a pint or quart of UHP, drop the dash of starter in and wait overnight is, well, quite easy and elegant .

Another related question: If I'm making a cheese that calls for extra cream can I use a UHP cream (that's all I can find here) without a problem if my milk is low-temperature pasteurized? Does the same apply for half-and-half (which is also UHP)?

Sorry, but I feel the need to jump in here. I do not agree with using straight UHP milk instead of heat sterilizing prior to inoculating a Mother Culture. UHP is usually flash processed at a much higher temperature, but for a VERY short period of time, like 2 SECONDS. That MAY be good enough, but killing "most of the bacteria" doesn't work for me. By contrast, I heat skim milk to 200-210F and hold for 30 minutes. Why cut corners just to save a little time?

If you've been following Sailor's method, then you could try what I do and see how it compares. Certainly for commercial purposes I would go with Sailor's. All I can say is that what I described above has worked well for me in the context of 10-11 litre makes. I had one cheese (a gouda) get contaminated, but other cheeses made from the same batch of ice cubes before and since have been fine so I'm pretty sure that's not the source of contamination.

I also would avoid using UHP cream if you can.

And thanks Sailor for the clarification on PS. I thought that was the case (that it wasn't a great one for mother cultures), but I've thought many things that were wrong and I wouldn't have been able to say why I thought that.

- Jeff

Logged

The wise do not always start out on the right path, but they do know when to change course.

I'm not sure if I messed it up, but the mixture hasn't thickened. Although it might have been the bacteria to begin with. I had it sitting in a cupboard for almost 2 weeks before I read up on their website that it needed to be refrigerated (I thought it'd be like yeast, and was properly dried out until moisture added), lesson learnt.

I would leave it for another day just to see if it thickens, but probably best not to use it even if it does as the culture has been slow growing if it works, and other bacteria may have got a foothold. It could be the culture has died, or the milk isn't in a warm enough place? Put move it to a higher shelf in your hotwater closet (if you have shelves in yours) to get it in a warm spot. I had it fail once due to the milk being kept just on the counter rather than in hotwater closet.

- Jeff

Logged

The wise do not always start out on the right path, but they do know when to change course.

Thanks Jeff and Sailor. Lately between business and family matters (3 grandkids in 1 month ) I haven't had time to make much cheese but the prospect of doing mother cultures always intrigued me Sailor after reading your post and my first effort that was successful. At one time I thought about repackaging bulk cultures in "mini" packets for the home cheese maker who would like to make different cheeses without having having to purchase more individual packets of DVI than they could use. It would be a good thing I think to develop the simplest (and safest!) way to prepare mother cultures for the occasional cheesemaker. Sounds like a good project .

A well prepared Mother Culture should only take a few hours to set. We make ours first thing in the morning. Milk is cooled to 115F for thermos and incubated at 115F in a dehydrator. Thermos are done in 6 or 7 hours. Milk for mesos is cooled to about 95-100F before inoculation. Then they are incubated at room temp overnight. The milk stays "warm" for quite some time to give the bacteria a good start. Next morning they are done.

I simply wouldn't trust a MC that took 2 days to set. Too much opportunity for undesirable bacteria to gain a foothold.

I agree with Sailor. The milk has been opened and given the desired culture was slow to get going, other undesirables are likely to have gotten in and established themselves as well. The idea is to get the desired culture to outcompete any pathogens by getting the desired culture to grow quickly before other wild bacteria move in. Next time, just put the milk in the warmer spot and see if that does it.

- Jeff

Logged

The wise do not always start out on the right path, but they do know when to change course.

If the cheese swells up like a rugby ball, that's a good sign (unless you've added Prop.Sherm. and have left the cheese in a warm spot where it's supposed to swell). If it smells like rotten food, or spoilage, that's not good (note, b.linens smells like dirty socks, etc, so not just any old "bad" smell). Basically, if you make sure you clean all your pots before (and after) making your cheese, and make sure anything that touches the milk is "sterilized" you should be fine. By "sterilized" I just mean, before you start put things like your spoons, stirring stick, etc, in the pot, pour in boiling water, and let everythign steam for awhile. Then, have two buckets, a blue and a red one. In the blue one, just put clean water. In the red one, put clean water and a cap of bleach. Now, when you are going to stirr, or take a temperature reading, etc, first dip the tool in the blue bucket (to rinse off any old milk, etc) then dip it in the red bucket (your sterilising solution), and then the milk. The small amount of bleach won't hurt your cheese make, but it helps to keep the equipment clean.

Logged

The wise do not always start out on the right path, but they do know when to change course.